Big block timing question

Hey got a quick question. I'm helping a buddy of mine with his 383 Cuda and am wondering what a good safe starting point would be timing wise. Specs are:

-69 383
-Stock rotating assembly so not sure of compression but guessing less than 9:1.
-Quick Fuel 750vs street carb
-OOTB 440source heads
-Comp XE275HL cam, 275/287 .525/.525 110
-Edelbrock Airgap Intake
-1 3/4 Hooker super comp long tubes
-MP Igniton, distributor, wires


I originally timed the initial with a vacuum gauge to maximum vacuum. This was just getting it going with the new carb, and this is still a relatively new combo. Later when I threw my timing light on it I was amazed to see that it was set to over 30* advance at idle. I wouldn't have thought it would need that much initial advance, so I just backed it down to 16 initial, and set the total to 35 as a starting point (basically what my sb is timed at). Is it normal for big blocks to want/need more timing than small blocks? This thing really acts like it would love some more timing but I'm afraid to give it any more. What do you think?